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首页> 外文期刊>Journal of Crystal Growth >The onset of spherulitic growth in crystallization of calcium carbonate
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The onset of spherulitic growth in crystallization of calcium carbonate

机译：碳酸钙结晶中球状生长的开始

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Batch and semi-batch crystallization experiments were performed in aqueous solutions for the three anhydrous polymorphs of calcium carbonate vaterite, aragonite and calcite to investigate the effect of crystallization parameters on the onset of spherulitic growth and particle morphology.rnAt a low initial supersaturation ratio of S_0=3.1 (90 ℃) aragonite crystallizes as monocrystalline needles while at a supersaturation ratio of S=9.9 the aragonite growth is on the edge of switching to a polycrystalline mode. Moreover, a lower temperature (30 ℃) seems to favour spherulites with a higher degree of branching than that was observed at 90 °C. This clearly demonstrates that besides the supersaturation ratio the temperature itself has a significant effect on the growth mode of the calcium carbonate particles. Calcite grows as monocrystalline cubical particles at 30 ℃, at the expense of metastable vaterite (S=1.9). Polycrystalline crystals of calcite start to form at a temperature of 10 ℃. However, unlike for aragonite this cannot be solely ascribed to the temperature as the supersaturation ratio is 16.3, and thus magnitudes are higher at 30 ℃. For the vaterite polymorph it is shown that the particle morphology exhibits smaller crystalline "subunits" at a higher initial supersaturation ratio of S_0=3 as compared to S_0=1.4. It is furthermore shown that the subunit "size" of particles can be changed arbitrarily (also from large to small) by manipulating the level of supersaturation.
机译：在水溶液中对碳酸钙球ate石，文石和方解石的三种无水多晶型物进行了分批和半分批结晶实验，以研究结晶参数对球晶生长和颗粒形态的影响。在低初始过饱和比S_0时= 3.1（90℃）文石结晶为单晶针状结晶，而过饱和比S = 9.9时，文石生长处于切换为多晶模式的边缘。此外，较低的温度（30℃）似乎比90℃下观察到的支化度更高的球晶更受欢迎。这清楚地表明，除了过饱和率以外，温度本身对碳酸钙颗粒的生长方式也具有显着影响。方解石在30℃时以单晶立方颗粒的形式生长，以亚稳球ate石为代价（S = 1.9）。方解石的多晶晶体在10℃的温度下开始形成。但是，与文石不同的是，由于过饱和比为16.3，因此不能仅将其归因于温度，因此在30℃时幅度更高。对于球ate石多晶型物，显示出与S_0 ＝ 1.4相比，颗粒形态在较高的初始过饱和比S_0 ＝ 3下表现出较小的晶体“亚基”。此外还表明，通过控制过饱和水平，可以任意改变颗粒的亚单位“尺寸”（也可以从大到小）。

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